Indicating protective covers for pipe flanges and valves



M y 24, 1955 M. F. SMITH ETAL 2,708,896

INDICATING PROTECTIVE COVERS FOR PIPE FLANGES AND VALVES Filed May 12,1954 FIGS 26 I OISTURE RESISTANT COATING cnemcn. \mcu CHANGESTRANSLUCENT COLOR UPON CONTACT MATERIAL WITH ACID OR ALKALI UnitedStates Patent INDICATING PROTECTIVE COVERS FOR PIPE FLANGES AND VALVESMillard F. Smith, Westport, and Edwards. Smith, Jr., Darien, Conn.

Application May 12, 1954, Serial No. 429,356

4 Claims. (Cl. 116-114) This invention relates generally to thetransmission of fluids through pipes and similar conduits, and moreparticularly to indicating protective covers for pipe and conduitconnections and valves. The invention lies in improved materials used informing these covers, and reference is made to our earlier Patent No.2,601,840, granted July 1, 1952, to Millard F. Smith and Edward S.Smith, Jr. for examples of the types of covers to which this inventionhas application.

The covers taught by this patent, while very effective, have sufferedfrom a disadvantage in that where the same are used in atmospheres whichare heavily laden with moisture vapors, there has been a tendency forthe chemical substance with which the fabric lining is impregnated to beaffected by small amounts of alkali or acid present in the vapors, sothat with passage of time, the covers would give the impression ofoverlying a leaking or damaged joint, when in fact the joint is inundamaged condition. Such indication has caused the removal of thecove-r and useless checking of the condition of the joints therebeneath,and the replacement of a fresh or unaflected cover with consequent wasteof time.

It is therefore among the principal objects of the present invention toprovide structure in the form of improved material employed in theconstruction pipe flange and valve, covers in which the above-describeddisadvantages have been substantially eliminated.

Another object of the invention lies in the provision of improved coverstructure which may remain impervious to the effects of moisture andvapor laden air containing small amounts of acid or alkali, but willreadily indicate the presence of a strong alkali or acid leaking fromcovered pipe flange joints.

Another object of the invention lies in the provision of pipe flangecover material possessing the above advantages, in which the cost offabrication may be of a reasonably low order, with consequent wide sale,distribution and use.

A further object of the invention lies in the provision of covermaterial which may be readily and easily inspected as has been the casein the prior art, and which may be fully as flexible and durable as thematerial is used in construction known in the prior art.

A feature of the invention lies in the fact that the material may beproduced at a cost closely approximating that found in the manufactureof prior art materials.

These objects and features, as well as other incidental ends andadvantages, will become more fully apparent in the progress of thefollowing disclosure, and be pointed out in the appended claims.

On the drawings, to which reference will be made in the specification,similar reference characters have been employed to designatecorresponding parts throughout the several views.

Figure l is a view in perspective of an indicating cover embodying theinvention in place upon a pipe flange structure of the covers 12 and 14is of a type fully described in the above-mentioned Patent No.2,601,840, the lines of interconnection 18 being engaged by stitch means20, or the like.

Referring to Figure 4 of the drawing, the laminated material 10 includesa woven textile layer 22, an outer transparent or translucent imperviouslayer 24, and an inner protective layer or coating 26.

The fabric layer 22 is preferably formed from woven fiberglass or otherinert textile material, although where considerations of cost areinvolved, the same may be formed from conventional canvas and the like.The layer 22 is impregnated with suitable chemicals depending upon thealkalinity or acidity of the potential leakage. Examples of suchnaterial are phenolphthalein, methyl red, methyl orange, litmus, thymolblue, and similar materials.

The outer impervious coating 24 is preferably formed from transparentvinyl material which may be applied as a coating, or as a thin sheetfused to the fabric layer 22 by heat sealing or other suitable means. Itis desirable that this material be either colorless or of a translucentwhite color, so that the effects of the impregnated chemical may beeasily viewed upon inspection through the same.

The inner moisture resistant coating 26 may be in the form of glue,varnish or similar materials which are essentially water resistant, butwhich are readily attacked by acids or caustics in water or liquidsolution. This coating is preferably applied after the integration ofthe layers 20 and 22, so that the same is not subjected to heat orheating processes during or after application.

In use, the material is so placed that the coating 26 is adjacent thepipe flange or valve, and the impervious layer 24 is disposed outwardly.During normal operation, the center fabric layer 22 is completelyenclosedand protected from the effects of the ambient air by theimpervious layer 24 on the outside and the moisture resistant layer orcoating 26 on the inside. Should this air contain an appreciable amountof acid or alkali, the vapor suspension of the same is normally unableto penetrate either layer or coating, and upon inspection the covershows no leakage. Should actual leakage occur from the valve or joint inquestion, the liquid solution or suspension of the acids or causticswill attack the glue or varnish coating 26, and in a relatively shorttime the coating will be penetrated to permit the acid or caustic orreach the fabric layer 22, thereby afiecting the impregnated chemical.Since the central layer is of woven or similar material, a wickingaction ocurs which causes the caustic or acid to be drawn into thefabric layer, thereby causing indicating color to appear in the sameover an area substantially larger than the penetrated opening in thewater resistant layer 26. Thus, once any penetration is accomplished,the inspecting party is quick to discern a leakage, so that promptaction may be taken.

If desired, coatings other than glue or varnish may be employed providedthe same are relatively impervious to water or moisture, and are quicklyaffected by the pressure of strong acid or alkaline solutions.

It may thus be seen that we have invented new and useful improvements inmaterials for forming indicating protective covers for pipe flanges,valves and similar devices, in which provision has been made for makingthe indicating chemical or material relatively impervious to ambientvapors, and nevertheless readily affected by the presence of substantialamounts of acids or alkalis carried by the joints 01 valves covered. Thecover material may be manufactured using techniques known and existingin the art, and at a cost very slightly higher than that reached in themanufacture of conventional cover mate rials. Where extreme economy isdesired, the central fabric layer may be eliminated, and the indicatingmaterial coated directly to the outer impervious layer, and covered bythe resistant coating in a manner suggested in the above-mentionedPatent No. 2,601,840. I

We wish it to be understood that we do not consider the inventionlimited to the exact details of structure shown and set forth in thespecification, for obvious modifications will occur to those skilled linthe art to which the present invention pertains.

We claim:

1. Material for forming protective indicating cover structurecomprising: a first Woven fabric layer impregnated with an indicatingmaterial; a moisture resistant structure comprising: a first wovenfabric layer impregnated with an indicating material; a moistureresistant coating soluble in acid superposing said layer; and atranslucent impervious layer on the side opposite said moistureresistant coating.

4. Material for forming protective indicating cover structurecomprising: a first woven fabric layer impregnated with an indicatingmaterial; a moisture resistant coating soluble in alkali superposingsaid layer; and a translucent impervious layer on the side opposite saidmoisture resistant coating.

References Cited in the file of this patent UNITED STATES PATENTSSnelling July 22, 1941 Smith July 1, 1952

